Timothy M. Bateman M.D. Co-Director, Cardiovascular Radiologic Imaging

Mid America Heart Institute Professor of Medicine

University of Missouri-Kansas City Kansas City, Missouri

Comparative Advantages of PET Over SPECT: Is PET Really Better?

Conflict of Interest Disclosure

Dr. Bateman declares that the following relationships constitute a potential conflict of interest with respect

to this presentation:

Research Grants: Astellas, GE, Lantheus, Philips, SpectrumDynamics Advisory Boards: Astellas, GE, Lantheus, SpectrumDynamics Royalties: ExSPECT IITM, ImagenPro/MD/QTM

Stock Ownership: Cardiovascular Imaging Technologies

Comparative Advantages of PET for Myocardial Perfusion Imaging

• Improved image quality vs traditional SPECT

• Higher diagnostic accuracy

• More data to strengthen interpretive confidence

• Lower dosimetry vs rest/stress SPECT

• Better through-put efficiency (Rb-82)

• Spatially-centric vs spatially-relative

• Improved prognostication

Situations When PET May Not Be Better Than SPECT for MPI

• Able to perform diagnostic-level exercise test

• Inability to lie still

• Slow circulation (CHF; PHTN) – Rb-82

• Morbid obesity – Rb-82

• Generator near EOL – Rb-82

• When adenosine only available vasodilator – Rb-82

Pharmacologic Stress Myocardial Perfusion Imaging

SPECT Rb-82 PET

Mid-LAD Ischemia RCA Ischemia

SPECT

PET

0

20

40

60

80

100

Men Women0

20

40

60

80

100

BMI<30 BMI>30

0

20

40

60

80

100

MVD

18% SPECT vs 4% PET studies were

in uncertain categories

SPECT

PET

Bateman, JNC 13: 24 – 33, 2006

0102030405060708090

Good Fair Sub-Optimal

Yoshinaga, JACC 48: 1029 – 39, 2006

Image Quality in 96 Pts Imaged With PET After a

Non-Definitive SPECT

ACCURACY BY GENDER ACCURACY BY BMI

MVD SENSITIVITY

48% 71%

*p=0.03

69% 84%

*p=0.05

67% 88%

*p=0.01

70% 87%

67% 85%

*p=0.05 *p=0.02

MIBI SPECT

Rb82 PET

Diagnostic Accuracy, PET

Beanlands and Youssef JNC 2010;17:683

Less than 5% of this data is from PET/CT

Jaarsma et al J Am Coll Cardiol 2012; 59: 1719-1728

SPECT, CMR, and PET for Detecting CAD

Rb-82 PET Vs SPECT for Diagnosis of Obstructive CAD: A Meta-Analysis

McArdle et al, J Am Coll Cardiol 2012; 60: 1828-1837

PET

SPECT

Rb-82 PET Vs SPECT for Diagnosis of Obstructive CAD: A Meta-Analysis Including Direct PET/SPECT

Comparison Studies

McArdle et al, J Am Coll Cardiol 2012; 60: 1828-1837

Rb-82 PET Vs SPECT for Diagnosis of Obstructive CAD: A Meta-Analysis Including Only AC-SPECT

p < 0.001

McArdle et al, J Am Coll Cardiol 2012; 60: 1828-1837

Information Content of a Contemporary PET MPI Study

1. High quality perfusion images: high count-density, minimal scatter, attenuation-corrected

2. High quality function images: each frame has high counts, each frame attenuation and scatter-corrected

3. Function images at rest and at peak stress (focus on changes in EF, ESV, average volume, & regional wall motion/thickening)

4. Rest and peak stress MBF

5. Presence and extent/severity of CAC

9 mA, 100 kVp, 5mm 5 secs breath-holding No ECG-gating

~ 0.18 mSv

• 492 pts

• 6 independent readers

• CACS categorized as 0, 1-9, 10-

99, 100-399, 400-999, >

1000

• 93% within 1 category

• Weighted kappa 0.89

Einstein et al, J Am Coll Cardiol 2010; 56: 1914 - 21

Rest EF 54% Peak Stress EF 60%

Rest ESV 29 Peak Stress ESV 25

Coronary Artery Calcium Score 0

67 y/o woman with atypical angina, multiple risk factors, in hospital with acute pancreatitis

Interpreted as low-risk scan, mild LAD distribution ischemia

One week later: Large anterior MI. Cath showed high-grade stenoses in the proximal

and mid portions of the LAD coronary artery

59 y/o male – normal PET MPI

1 month later = lateral MI Cath = LCx thrombus, 75% stenoses in LAD and RCA

Dosimetry Estimates for Radionuclide Myocardial Perfusion Imaging

Tracer Stress Dose

Rest Dose

mSv

Tc-99m MIBI 30 mCi 10 mCi 12 mSv Tc-99m MIBI SO 30 mCi 9 mSv

Tc-99m MIBI SO-SD 2 – 4 mCi 0.7 – 2 mSv Rb-82 40 mCi 40 mCi 3.6 mSv

NH3-Ammonia 20 mCi 20 mCi 3 mSv

Rb-82 ECG-Gated Rest/Stress Acquisition Protocol for Dedicated or Hybrid PET/CT

1 3.5 3.5

Tx Scan

Rb-82 40 mCi

Emission Scan, 3D

with gating

1

Tx Scan

Rb-82 40 mCi

1

Emission Scan, 3D

with gating

Dipyridamole, Dobutamine

Stress

25 minutes

Dorbala et al, JACC Imaging 2009;2:846-854

PET MPI Risk Stratification % Abnl Myocardium

As Function of LVEF Reserve

Lertsburapa et al, JNC 15: 745-753, 2008

MBFR Is an Independent Predictor of Major Adverse Cardiac Events (677 pts with median f/u 387days)

Ziadi et al, JACC 2011; 58: 740 - 748

Improved Risk Assessment With PET CFR

Murthy et al, Circulation October 17, 2011

Kaplan–Meier Survival Curves

Tonino PA et al. N Engl J Med 2009;360:213-224

Johnson et al, J Am Coll Cardiol Img 2012;5:193–202)

PET Coronary Flow Reserve Vs Tracer Uptake

Johnson et al, J Am Coll Cardiol Img 2012;5:193–202)

Theoretic and Practical Benefit of PCI: CFR Vs FFR

Radionuclide Myocardial Perfusion Imaging in 2013: Moving Away From One Test For All Purposes

MPI

Stress-Only SPECT

Rest/Stress SPECT

Rest/Stress PET